A valve construction of the aforementioned type is known from Federal Republic of Germany DE 39 17 242, corresponding to European Patent No. EP 0,391,269, expressly incorporated herein by reference. The prior art system, however, incorporates base plates which receive only on-off or directional valves. Such valve batteries are advantageous because they have a small structural size, a high rate of flow and a minimum weight. Furthermore, such valve batteries assure short switching times. In the prior art system of DE 39 17 242, the installation of individually controllable directional valves required the development of miniature solenoid valves from which unusually high flow rates are required. Such valve batteries permit a simple and rapid application to existing pressure-fluid systems and the control, for instance, of grippers, cylinders, rotary drives, handling devices, and the like.
The use of such valve batteries configured as on-off valves, which may be directional valves for regulating a servomotor is, however, not sufficient in certain cases for the necessary directional control processes. Thus, the known solution entirely lacks control functions, which are necessary in certain applications.